Being sent abroad on assignment sounds impossibly glamorous, but in reality relocation can be a stressful and expensive experience for both company and employee.

There is a high chance that it won't work out and the squeeze on corporate budgets means that you are only likely to be offered a chance to work abroad if you are relatively senior within an organisation or have very specific skills.

'Relocation has recently undergone some significant changes,' says Jeremy Tipper, managing director of Capital Consulting. 'Companies have become more selective because they know, and acknowledge, that relocation to be a very expensive activity regardless of whether it is domestic or international. It is offered much less frequently than it used to be and in some firms it is regarded as such a significant cost that human resources departments set budget limits or quotas of numbers of staff they can relocate.

'Some organisations offer very attractive relocation packages - for example, they will help you with the move by paying the stamp duty on your house, assist in finding a new property and sort out arrangements for your family, including schooling for the children.'

Traditionally, the chance to work abroad was seen as a big career opportunity and a quick route to promotion. Now that employees have begun to think more about their work-life balance and their quality of life, other factors come into play.

'It is not just about your career progression,' says Tipper. 'You need to look at it in the context of your whole life. You can't take the decision to go through an upheaval of that kind on your own. There is likely to be impact on your partner or family and the emotional stresses of moving can be greater for them than for you.'

He cites his experience when he worked for a recruitment company and was given the opportunity to start up new operations in New Zealand and Australia. 'Despite it being a great job, my wife and I only stayed out there for 15 months because it was a long way from home and she found it difficult to get work,' he says. 'While I was working 80 hours a week she was isolated, not knowing many people, and unable to continue her career.'

You also need to think about the financial implications of the upheaval your life will go through. What will happen to your UK pension contributions, life insurance policies and mortgage? Will your employer help you with these? And what will happen to your home and your car when you are out of the country?

Nigel Passingham of Crown Relocations says that people often underestimate the impact the move will have on families: 'We often find it is the family who have to face the cultural issues and do a lot of organising when they arrive.'

Anything over one year is considered a long-term assignment, and two to three years is considered a normal length for an international relocation. Under one year it is generally classed as short-term and tends to be linked to overseeing a project. On some short-term assignments the family is not expected to live abroad and the employee is given free flights back home instead.

'Companies are realising that the cost of failed relocations is very high, and so encourage candidates to do a preview trip,' says Passingham. 'The key objective is to get the family settled as soon as possible so that the employee can be productive for the organisation.'

Organisations such as Crown Relocations handle visa and work permits and search for suitable accommodation and schools. They also organise tenancy agreements, renew contracts and advise on repatriation services at the end of the assignment. Given that the family not settling is a major reason for a failed assignment, companies are keen to ensure that they are settled in as smoothly as possible.

Tipper says employers are looking at 'the total cost of hire' - not just the salary they will have to pay the person but also the cost of recruitment fees, interview, visa and relocation allowance. This is why relocation tends to be less common and the packages slightly less generous than they used to be.

'The supply of good people is now more in equilibrium with demand and companies are becoming more reluctant to pay hefty relocation packages,' he adds. 'In the late 1990s, when the marketplace was overheated, organisations were taking part in the "war for talent". That is now less of a factor.'

Closer to home, he is seeing a trend towards people staying in the UK but choosing to relocate their families to smaller towns. 'The UK population in general terms are pretty mobile and we are seeing people who have careers with major companies in big cities deciding to relocate further outside the major conurbations. A good example is Vodafone, which is based in Newbury, and which in the last few years has seen a significant improvement in its ability to attract people from London.'